An investigation into sinterability improvements of 316L binder jet printed parts

Metal binder jet additive manufacturing (BJAM) process is catching the automotive, aerospace and medical industry’s attention as it is fast, economical, and enables fabrication of complex geometries. While other conventional powder metallurgy (PM) processes like hot isostatic pressing (HIP) and metal injection molding (MIM) already have well-defined pre- and post- process parameters, they still need to be established for BJAM. This paper evaluates the effect of particle size distribution (PSD) and green state density on the sintering of 316L powders using the master sintering curve (MSC) concept. Three powders with different PSDs are used to manufacture test coupons produced with similar green densities for handmade samples and differing green densities using BJAM. The MSC results show the effect of the PSD and green densities on the sintering behavior of the powders. A powder with a bimodal distribution of particle size is shown to have the best sintering characteristics for BJAM by allowing higher initial packing density.